function Map() {
    /** 存放键的数组(遍历用到) */
    this.keys = new Array();
    /** 存放数据 */
    this.data = new Object();

    /**
     * 放入一个键值对
     * @param {String} key
     * @param {Object} value
     */
    this.put = function (key, value) {
        if (this.data[key] == null) {
            this.keys.push(key);
        }
        this.data[key] = value;
    };

    /**
     * 获取某键对应的值
     * @param {String} key
     * @return {Object} value
     */
    this.get = function (key) {
        return this.data[key];
    };

    /**
     * 删除一个键值对
     * @param {String} key
     */
    this.remove = function (key) {
        var k=-1;
        for(var i=0;i<this.keys.length;i++){
            if(this.keys[i]==key){
                k=i;
            }
        }
        if(k==-1){
            throw 'remove error'
        }

        this.keys.splice(k,1);
        this.data[key] = null;
    };

    /**
     *
     *  貌似有问题
     *
     * 遍历Map,执行处理函数
     *
     * @param {Function} 回调函数 function(key,value,index){..}
     */
    this.each = function (fn) {
        if (typeof fn != 'function') {
            return;
        }
        var len = this.keys.length;
        for (var i = 0; i < len; i++) {
            var k = this.keys[i];
            fn(k, this.data[k], i);
        }
    };

    /**
     *
     * 貌似有问题
     *
     * 获取键值数组(类似Java的entrySet())
     * @return 键值对象{key,value}的数组
     */
    this.entrys = function () {
        var len = this.keys.length;
        var entrys = new Array(len);
        for (var i = 0; i < len; i++) {
            entrys[i] = {
                'key': this.keys[i],
                'value': this.data[i]
            };
        }
        return entrys;
    };

    /**
     * 判断Map是否为空
     */
    this.isEmpty = function () {
        return this.keys.length == 0;
    };

    /**
     * 获取键值对数量
     */
    this.size = function () {
        return this.keys.length;
    };

    /**
     * 重写toString
     */
    this.toString = function () {
        var s = "{";
        for (var i = 0; i < this.keys.length; i++, s += ',') {
            var k = this.keys[i];
            s += k + "=" + this.data[k];
        }
        s += "}";
        return s;
    };


    /**
     * 返回所有key
     * @returns {Array}
     */
    this.getKey=function(){
        return this.keys;
    };

}
